Resonators in fluid lines have been known and in use for a long time for the purpose of avoiding unpleasant acoustic emissions during oscillations of the fluid in the fluid line. They are nowadays made mostly from plastics, above all injection-molded parts, but also blow-molded parts, being employed. Injection-molded parts have the disadvantage that their production is mostly very complex and costly. By contrast, blow-molding is a relatively cost-effective production method, and therefore the objective is increasingly to use blow-molded parts.
DE 10 2008 016 690 A1 shows a generic resonator in which both resonator parts are formed as blow-molded parts. The parts have, in each case, a collar and are connected to one another in an airtight manner at these collars.
The technical teaching disclosed in DE 10 2008 016 690 A1 makes it possible to have only resonators with only one resonant chamber. This single chamber is connected to the actual fluid line by means of an annular gap 19 shown in FIGS. 5 and 6. Although this solution is distinguished by its great simplicity, the possibilities for using it are nevertheless restricted, since multichamber systems cannot be implemented without further outlay.
U.S. Pat. No. 5,806,480 discloses a fluid line which has, in a longitudinal section, two pipes which are arranged one in the other and between which is arranged a chamber encasing the inner pipe. In this case, this chamber communicates with the interior of the inner pipe via orifices which are incorporated into the inner pipe. To produce this pipe piece, the inner pipe is first injection-molded. A blank for the outer pipe is then produced via an extrusion method such that the blank encases the inner pipe. The outer pipe blank is subsequently formed by means of a blow-molding method in order to produce the outer pipe.
To carry out the extrusion and blow-molding operations, a complicated die is required here, since the entire line piece has to be capable of being introduced into the die (see FIG. 3 of U.S. Pat. No. 5,806,480) and a specific die has to be provided correspondingly for each line piece.